<div style="display:table;height:100%;width:100%;">
    <div style="display:table-cell;vertical-align:middle;padding:0 10%;">
        <div class="alert alert-block alert-info">
            <h4>Info</h4>
            <div class="msg">Please select period above and an agent on the left.</div>
        </div>
    </div>
</div>